Eutectic salts

ABSTRACT

Some embodiments include a molten salt system comprising a reactor with a salt mixture. In some embodiments, the salt mixture includes uranium and a eutectic salt. The eutectic salt may include one or more of sodium fluoride, potassium fluoride, aluminum fluoride, zirconium fluoride, lithium fluoride, beryllium fluoride, rubidium fluoride, magnesium fluoride, calcium fluoride, sodium chloride, potassium chloride, aluminum chloride, zirconium chloride, lithium chloride, beryllium chloride, rubidium chloride, magnesium chloride, and calcium chloride. The eutectic salt may have a melting point less than about 800° C.

BACKGROUND

Molten salt reactors are a class of nuclear fission reactors in which the primary nuclear reactor coolant and/or the fuel is a molten salt mixture. Molten salt reactors offer multiple advantages over conventional nuclear power plants.

SUMMARY

Some embodiments of the disclosure include eutectic salts that may be used in a molten salt reactor. The eutectic salt, for example, may include: a salt mixture comprising one or more salts selected from the group consisting of sodium fluoride, potassium fluoride, aluminum fluoride, zirconium fluoride, lithium fluoride, beryllium fluoride, rubidium fluoride, magnesium fluoride, calcium fluoride, and uranium fluoride. In some embodiments, the eutectic salt has a melting point less than about 800° C.

In some embodiments, the salt mixture comprises sodium fluoride and potassium fluoride. In some embodiments, the salt mixture comprises sodium fluoride (40-60 mol %) and potassium fluoride (40-60 mol %).

In some embodiments, the salt mixture comprises sodium fluoride, potassium fluoride, and magnesium fluoride. In some embodiments, the salt mixture comprises sodium fluoride (40-60 mol %), potassium fluoride (40-70 mol %), and magnesium fluoride (0-20 mol %).

In some embodiments, the salt mixture comprises sodium fluoride, potassium fluoride, and calcium fluoride. In some embodiments, the salt mixture comprises sodium fluoride (40-60 mol %), potassium fluoride (40-70 mol %), and calcium fluoride (0-20 mol %).

In some embodiments, the salt mixture comprises sodium fluoride (40-60 mol %), potassium fluoride (40-70 mol %), magnesium fluoride (0-20 mol %), and calcium fluoride (0-20 mol %).

In some embodiments, the salt mixture comprises lithium fluoride, sodium fluoride and potassium fluoride.

In some embodiments, the uranium fluoride comprises uranium-233 or uranium-235.

In some embodiments, the melting point of the eutectic salt is less than about 750° C. In some embodiments, the melting point of the eutectic salt is less than about 650° C. In some embodiments, the melting point of the eutectic salt is less than about 550° C. In some embodiments, the melting point of the eutectic salt is about 710° C.

Some embodiments include a molten salt system comprising a reactor with a salt mixture. In some embodiments, the salt mixture includes uranium and a eutectic salt. The eutectic salt may include one or more of sodium fluoride, potassium fluoride, aluminum fluoride, zirconium fluoride, lithium fluoride, beryllium fluoride, rubidium fluoride, magnesium fluoride, calcium fluoride, sodium chloride, potassium chloride, aluminum chloride, zirconium chloride, lithium chloride, beryllium chloride, rubidium chloride, magnesium chloride, and calcium chloride. The eutectic salt may have a melting point less than about 800° C.

In some embodiments, the melting point of the eutectic salt is less than about 750° C. In some embodiments, the melting point of the eutectic salt is less than about 650° C. In some embodiments, the melting point of the eutectic salt is less than about 550° C. In some embodiments, the melting point of the eutectic salt is about 710° C.

Some embodiments include a eutectic salt comprising uranium, and one or more salts selected from the group consisting of sodium fluoride, potassium fluoride, lithium fluoride, sodium chloride, potassium chloride, and magnesium chloride. In some embodiments, the eutectic salt has a melting point less than about 800° C.

In some embodiments, the melting point of the eutectic salt is less than about 750° C. In some embodiments, the melting point of the eutectic salt is less than about 650° C. In some embodiments, the melting point of the eutectic salt is less than about 550° C. In some embodiments, the melting point of the eutectic salt is about 710° C.

In some embodiments, the eutectic salt comprises sodium fluoride and potassium fluoride. In some embodiments, the salt mixture comprises sodium fluoride (40-60 mol %) and potassium fluoride (40-60 mol %).

In some embodiments, the eutectic salt comprises sodium fluoride, potassium fluoride, and magnesium fluoride. In some embodiments, the salt mixture comprises sodium fluoride (40-60 mol %), potassium fluoride (40-70 mol %), and magnesium fluoride (0-20 mol %).

In some embodiments, the eutectic salt comprises sodium fluoride, potassium fluoride, and calcium fluoride. In some embodiments, the salt mixture comprises sodium fluoride (40-60 mol %), potassium fluoride (40-70 mol %), and calcium fluoride (0-20 mol %).

In some embodiments, the salt mixture comprises sodium fluoride (40-60 mol %), potassium fluoride (40-70 mol %), magnesium fluoride (0-20 mol %), and calcium fluoride (0-20 mol %).

BRIEF DESCRIPTION OF THE FIGURES

These and other features, aspects, and advantages of the present disclosure are better understood when the following Detailed Description is read with reference to the accompanying drawings.

FIG. 1 is a diagram of a molten salt reactor system according to some embodiments.

FIG. 2 is a diagram of a chemical separation subsystem of a molten salt reactor according to some embodiments.

FIG. 3 is a diagram of a chemical separation subsystem of a molten salt reactor with the electrode in a raised position within the chemical separation chamber according to some embodiments.

FIG. 4 is a diagram of a chemical separation subsystem of a molten salt reactor with the electrode in a lowered position and disposed within the solvent pool according to some embodiments.

FIG. 5 is a diagram of a chemical separation subsystem attached with molten salt reactor according to some embodiments.

FIG. 6 is another diagram of a chemical separation subsystem attached with molten salt reactor according to some embodiments.

FIG. 7 is a flowchart representing a process of using an electrode to remove fission products from a molten salt reactor according to some embodiments.

DETAILED DESCRIPTION

Specific eutectic salts and/or associated systems and methods are disclosed for use in a molten salt reactor. A molten salt reactor may include a nuclear fission reactor in which the reactor coolant, or even the fuel itself, is a molten salt mixture. In some embodiments, molten salt reactors can run at higher temperatures than water-cooled reactors for a higher thermodynamic efficiency, while staying at or near ambient pressure. In some embodiments, the fuel in a molten salt reactor may include a molten mixture of fluoride salts (e.g., sodium fluoride and magnesium fluoride) with dissolved uranium (U-235 or U-233) fluorides (UF_(x)). In some embodiments, the uranium may be low-enriched uranium (where 5% or less of the Uranium is U-235), uranium-233, uranium-235, uranium 238, or high enriched uranium (where 5% or more of the Uranium is U-235). In some embodiments, the rate of fission in a molten salt reactor can be inherently stable.

FIG. 1 is a diagram of a molten salt reactor system 100 according to some embodiments. The molten salt reactor system 100 may include a reactor 102, a chemical separation subsystem (e.g., including chemical separation chamber 120), safety systems (e.g., including emergency dump tanks 165), and turbines 145.

The reactor 102 may include any type of molten salt fission device or system whether or not it includes a reactor. The reactor 102 may include a liquid-salt very-high-temperature reactor, a liquid fluoride reactor, a liquid fluoride thorium reactor, a liquid chloride reactor, a sodium chloride reactor, a magnesium chloride reactor, a potassium chloride reactor, a liquid chloride thorium reactor, a liquid salt breeder reactor, a liquid salt solid fuel reactor, a high flux water reactor with a uranium-salt or thorium salt target, etc. The reactor 102, for example, may employ one or more molten salts with a fissile material. The molten salt, for example, may include any salt comprising Fluorine, Chlorine, Lithium, Sodium, Potassium, Beryllium, Zirconium, Rubidium, Magnesium etc., or any combination thereof. Some examples of molten salts may include LiF, LiF—BeF₂, 2LiF—BeF₂, LiF—BeF₂—ZrF₄, NaF—BeF₂, LiF—NaF—BeF₂, LiF—ZrF₄, LiF—NaF—ZrF₄, KF—ZrF₄, RbF—ZrF₄, LiF—KF, LiF—RbF, LiF—NaF—KF, LiF—NaF—RbF, BeF₂—NaF, NaF—BeF₂, LiF—NaF—KF, NaF—MgF, NaF—MgF—KF etc. In some embodiments, the molten salt may include sodium fluoride, potassium fluoride, aluminum fluoride, zirconium fluoride, lithium fluoride, beryllium fluoride, rubidium fluoride, magnesium fluoride, and/or calcium fluoride

In some embodiments, the molten salt may include any of the following possible salt eutectics. Many other eutectics may be possible. The following examples also include the melting point of the example eutectics. The molar ratios are examples only. Various other eutectics may be used.

-   -   LiF—NaF (60-40 mol %) 652° C.     -   LiF—KF (50-50 mol %) 492° C.     -   LiF—NaF—KF (46.5-11.5-42 mol %) 454° C.     -   LiF—NaF—CaF₂ (53-36-11 mol %) 616° C.     -   LiF—NaF—MgF₂—CaF₂ (˜50-˜30-˜10-˜10 mol %)˜600° C.     -   LiF—MgF₂—CaF₂ (˜65-˜12-˜23 mol %) 650-725° C.     -   LiF—BeF₂ (66.5-33.5 mol %) 454° C.     -   NaF—BeF₂ (69-31 mol %) 570° C.     -   LiF—NaF—BeF₂ (15-58-27 mol %) 480° C.     -   LiF—NaF—ZrF₄ (37-52-11 mol %) 604° C.     -   LiF—ThF₄ (71-29 mol %) 565° C.     -   NaF—ThF₄ (77.5-22.5 mol %) 618° C.     -   NaF—ThF₄ (63-37 mol %) 690° C.     -   NaF—ThF₄ (59-41 mol %) 705° C.     -   LiF—UF4 (73-27 mol %) 490° C.     -   NaF—UF₄ (78.5-21.5 mol %) 618° C.     -   LiF—NaF—UF₄ (24.3-43.5-32.2 mol %) 445° C.

In some embodiments, the salt eutectic may include a mixture of UrF₄ and ThF₄ with a total mole ratio of about 41% (mol %) and NaF with a mole ratio of about 59%. The total mole ratio, for example, of the UrF₄ and ThF₄ mixture may be about 41%. The ratio UrF₄ and ThF₄ within the mixture may include any ratio. For example, the UrF₄ and ThF₄ mixture may include about 50% UrF₄ and about 50% ThF₄, or the mixture may include about 25% UrF₄ and about 75% ThF₄, or the mixture may include about 75% UrF₄ and about 25% ThF₄, or the mixture may include about 10% UrF₄ and about 90% ThF₄, or the mixture may include about 90% UrF₄ and about 10% ThF₄, etc.

In some embodiments, the salt eutectic may include a mixture of UrF₄ and ThF₄ with a total mole ratio of about 40%-60% (mol %) and NaF with a mole ratio of about 60%-40%.

The reactor 102 may include a reactor blanket 105 that surrounds a reactor core 110. A plurality of rods 115 may be disposed within the reactor core 110. The reactor core 110, for example, may include a Uranium rich molten salt such as, for example, UF₄—FLiBe. The reactor blanket 105 may include a breeding actinide salt that can produce Uranium for the reactor core 110. The reactor blanket 105 may include a thorium rich fluoride salt. For example, the reactor blanket 105 may include thorium-232, which through neutron irradiation becomes thorium-233. Thorium-233 has a half-life of 22 minutes and through beta decay becomes protactinium-233. Then, through a second beta decay protactinium-233, which has a half-life of 26.97 days, becomes uranium-233, which is additional fuel for the reactor core 110.

The rods 115 may include any material that may act as a neutron energy moderator such as, for example, graphite, ZrH_(x), light water, heavy water, beryllium, etc. The neutron energy moderator may be selected or not used at all based on the desire for thermal, epithermal, or fast spectrum neutrons within the reactor core 110.

In some embodiments, the reactor system 100 may include a chemical separation subsystem. The chemical separation subsystem, for example, may include a chemical separation chamber 120 and/or a chemical separation loop 125. The chemical separation subsystem, for example, may be used to extract fission products and purify the base salts. A list of fission products can be found, for example, at https://www-nds.iaea.org/wimsd/fpyield.htm#T1 and/or at https ://www-nds.iaea.org/wimsd/fpyield.htm#T2. The chemical separation subsystem, for example, may remove fission products without removing actinides (e.g., Uranium 233, Uranium 235, and/or Plutonium 239, etc.) from the reactor core 110. FIGS. 2, 3, and 4 illustrate examples of a chemical separation subsystem.

The safety subsystem may include an emergency dump conduit 170, a freeze plug 160, and a plurality of emergency dump tanks 165. The emergency dump tanks 165 are connected with the reactor core 110 via the dump conduit 170. The freeze plug 160 may be an active element that keeps the fissile material within the reactor core 110 unless there is an emergency. If the freeze plug 160, for example, loses power or is otherwise triggered, the dump conduit is opened and the fissile material in the reactor core 110 is dumped into the dump tanks 165. The dump tanks 165 may include materials such as, for example, energy moderating materials. The dump tanks 165, for example, may be placed in a location where any reactions can be controlled. The dump tanks 165, for example, may be sized to preclude the possibility of a sustained reaction.

FIG. 2 is a diagram of a chemical separation subsystem 200 of a molten salt reactor according to some embodiments. The chemical separation subsystem 200 includes a molten salt chemical separation channel 205 that can conduct molten salt from a molten salt chamber (e.g., reactor core 110). The molten salt chemical separation channel 205 may connect with the molten salt loop conduit 220, which may channel molten salt from the molten salt chamber to the molten salt chemical separation channel 205. The chemical separation channel 205 may feed molten salt into the molten salt reservoir 210, 215. The molten salt reservoir 210, 215 may fill or partially fill with molten salt via the molten salt chemical separation channel 205. In some embodiments, bismuth or other chemicals may be constrained, placed, or disposed within the molten salt reservoir 210, 215 by a membrane or mesh, for example, to chemically remove additional fission products. Molten salt may flow through the molten salt reservoir 210, 215 and return to the molten salt chamber via molten salt return conduit 245.

In some embodiments, the surface level 225 of the molten salt within the molten salt chemical separation channel 205 may separate the molten salt chemical separation channel 205 and the chemical separation chamber 260. In some embodiments, the chemical separation chamber 260 may be filled with an inert gas or a vacuum that may, for example, keep the molten salt surface 225 from being exposed to unwanted reactions or oxidation.

In some embodiments, an electrode 230 may be dipped within the molten salt within the molten salt chemical separation channel 205. The electrode 230 may include Uranium. The electrode may be coupled with a raise and swivel gantry 235. The raise and swivel gantry 235 may be a mechanical mechanism that can raise (see FIG. 3), swivel, and lower (see FIG. 4) the electrode 230 into a solvent receptacle 240. The solvent receptacle 240 may include a solvent. In some embodiments, the solvent may comprise any solvent that includes Ethelyn glycol. In some embodiments, the solvent may be held at or near about room temperature. The raise and swivel gantry 235 may include a one or more of motors, actuators, gears, pulleys, solenoids, cables, etc. that can effectuate the movement of the electrode 230.

In some embodiments, an electrical potential may be placed on the electrode 230 while the electrode is in contact with the molten salt (e.g., actinide bearing salt). In some embodiments, an electrical potential may not be required and the electrode 230 will merely be a conductor while the electrode is in contact with the molten salt. In some embodiments, the electric potential may be a direct current or an alternating current electrical potential. A second electrode may be in contact with the molten salt to complete the circuit. The second electrode can be an electrode coupled with any portion of the chemical separation subsystem 200 and/or may be part of a vessel wall of the chemical separation subsystem 200 such as, for example, the second electrode may be part of the vessel wall of the molten salt chemical separation channel 205 and/or the vessel wall of the molten salt loop conduit 220. The electric potential between the electrode 230 and the second electrode may produce an electrochemical reaction between fission products within the molten salt and the electrode 230. In some embodiments, the electrochemical reaction may cause fission products to be plated on the electrode 230.

In some embodiments, the magnitude of the electric potential, the magnitude of the current applied to the electric potential, the composition of the molten salt, the type and composition of the fission products dissolved in the salt, and/or the material comprising the electrode 230 may determine the reactants that react with the electrode 230. Additionally or alternatively, in some embodiments, the frequency of an alternating electric potential, the frequency of the alternating current applied to the electric potential, the composition of the molten salt, and/or the material comprising the electrode 230 may determine the reactants that react with the electrode 230

In some embodiments, the raise and swivel gantry 235 may be disposed partially within the chemical separation chamber 260. In some embodiments, one or more of motors, actuators, gears, pulleys, solenoids, cables, etc. may be coupled with and/or part of the raise and swivel gantry 235. In some embodiments, the one or more of motors, actuators, gears, pulleys, solenoids, cables, etc. may be disposed external to the chemical separation chamber 260 that cause the raise and swivel gantry 235 to raise and/or swivel the electrode 230.

In some embodiments, the chemical separation chamber 260 may include a getter plug 250. The getter plug 250, for example, may include magnesium carbonate, depleted uranium, silver, or copper etc., and collect various chemicals, especially gasses such as tritium, hydrogen, deuterium, iodine, xenon, etc. In some embodiments, the getter plug 250 may use a pneumatic or mechanical system to remove and replace the (potentially saturated) getter in order to pull out chemicals from the chemical separation chamber 260.

In some embodiments, the chemical separation chamber 260 may include a gaseous release port 255. The gaseous release port 255, for example, may collect gaseous products from the chemical separation chamber 260 such as, for example, krypton, xenon, iodine, helium etc.

FIG. 3 is a diagram of a chemical separation subsystem 200 of a molten salt reactor with the electrode 230 in a raised position within the chemical separation chamber 260 according to some embodiments. In this figure, the one or more of motors, actuators, gears, pulleys, solenoids, cables, etc. have been engaged to raise the raise and swivel gantry 235.

FIG. 4 is a diagram of a chemical separation subsystem 200 of a molten salt reactor with the electrode 230 in a lowered position and disposed within the solvent receptacle 240 according to some embodiments. In some embodiments, when the electrode 230 is in the lowered position and disposed within the solvent receptacle 240, the electric potential between the electrode 230 and the second electrode may be reversed and produce an electrochemical reaction between the fission products on the electrode and the solvent within the solvent receptacle 240. In some embodiments, when the electrode 230 is in the lowered position and disposed within the solvent receptacle 240, the frequency or magnitude of the potential between the electrode 230 and the second electrode may be changed to produce an electrochemical reaction between the fission products on the electrode and the solvent within the solvent receptacle 240. In some embodiments the fission products may be released, dissolved, and/or deposited into the solvent.

In some embodiments, the solvent receptacle 240 may be coupled with a solvent processing subsystem such as, for example, via a tube and/or a solenoid that allows solvent to flow from the solvent receptacle 240 to the solvent processing subsystem. In some embodiments, the fission products may be separated from the solvent and/or further processed.

FIG. 5 is a diagram of a chemical separation subsystem 200 attached with molten salt reactor 260 (e.g., reactor 102) according to some embodiments. FIG. 6 is another diagram of a chemical separation subsystem 200 attached with molten salt reactor 260 according to some embodiments. In some embodiments, the chemical separation subsystem 200 may be coupled with the molten salt reactor 260 via the molten salt return conduit 245 and/or the molten salt loop conduit 220.

FIG. 7 is a flowchart representing a process 700 for using an electrode to remove fission products from a molten salt reactor according to some embodiments. At block 705 an electrode may be exposed to a molten salt. The electrode, for example, may include electrode 230. The molten salt may include but not be limited to any molten salt described in this document.

At block 710 an electrical potential is provided to the electrode. The electrical potential, for example, may vary in voltage and/or frequency depending on the type of molten salts, the molten salt mixture, and/or the type of fission products desired to extract from the molten salt. The electric potential, for example, may be a potential between the electrode and a second electrode disposed elsewhere in the molten salt. The electric potential between the electrode and the second electrode may produce an electrochemical reaction between fission products within the molten salt and the electrode. In some embodiments, the electrochemical reaction may cause fission products to be plated on the electrode.

At block 715 the electrode may be removed from the molten salt. This can be accomplished in any number of ways. For example, the electrode may be removed using a raise and swivel gantry. As another example, the electrode may be removed using one or more of motors, actuators, gears, pulleys, solenoids, etc. As another example, the electrode may be removed from the molten salt by removing the molten salt.

At block 720 the electrode may be exposed to a solvent. For example, the electrode can be moved to a solvent receptacle. As another example, the chamber where the electrode is disposed may be filled with a solvent after the molten salt has been removed.

At block 725 the electrode may be exposed to an electrical potential. In some embodiments, the electrical potential provided while the electrode is disposed in the solvent may be reversed relative to the electrical potential provided at block 710. In some embodiments, the electrical potential, for example, may vary in voltage and/or frequency depending on the solvent composition and/or the type of fission products. The electric potential, for example, may be a potential between the electrode and a third electrode disposed elsewhere in the solvent. The electric potential between the electrode and the third electrode may produce an electrochemical reaction between fission products plated on the electrode such that the fission products are dissolved in the solvent.

At block 730 the electrode may be removed from the solvent.

The process 700 may be repeated any number of times. The process 700 may also include additional blocks or steps. In addition or alternatively, any number of blocks of the process 700 may be removed or deleted.

In some embodiments, an electrode may be held stationary within a chemical separation subsystem. Molten salt and solvent may alternately flow into the chemical separation subsystem as electrical potential on the electrode is correspondingly reversed to collect fission material from the molten salt and dissolve fission material in the solvent.

Unless otherwise specified, the term “substantially” means within 5% or 10% of the value referred to or within manufacturing tolerances. Unless otherwise specified, the term “about” means within 5% or 10% of the value referred to or within manufacturing tolerances.

The conjunction “or” is inclusive.

Numerous specific details are set forth herein to provide a thorough understanding of the claimed subject matter. However, those skilled in the art will understand that the claimed subject matter may be practiced without these specific details. In other instances, methods, apparatuses or systems that would be known by one of ordinary skill have not been described in detail so as not to obscure claimed subject matter.

The system or systems discussed herein are not limited to any particular hardware architecture or configuration.

The use of “adapted to” or “configured to” herein is meant as open and inclusive language that does not foreclose devices adapted to or configured to perform additional tasks or steps. Additionally, the use of “based on” is meant to be open and inclusive, in that a process, step, calculation, or other action “based on” one or more recited conditions or values may, in practice, be based on additional conditions or values beyond those recited. Headings, lists, and numbering included herein are for ease of explanation only and are not meant to be limiting.

While the present subject matter has been described in detail with respect to specific embodiments thereof, it will be appreciated that those skilled in the art, upon attaining an understanding of the foregoing, may readily produce alterations to, variations of, and equivalents to such embodiments. Accordingly, it should be understood that the present disclosure has been presented for purposes of example rather than limitation, and does not preclude inclusion of such modifications, variations and/or additions to the present subject matter as would be readily apparent to one of ordinary skill in the art. 

That which is claimed:
 1. A eutectic salt comprising: a salt mixture comprising: uranium, and one or more salts selected from the group consisting of sodium fluoride, potassium fluoride, aluminum fluoride, zirconium fluoride, lithium fluoride, beryllium fluoride, rubidium fluoride, magnesium fluoride, calcium fluoride, sodium chloride, potassium chloride, aluminum chloride, zirconium chloride, lithium chloride, beryllium chloride, rubidium chloride, magnesium chloride, and calcium chloride; wherein the eutectic salt has a melting point less than about 800° C.
 2. The eutectic salt according to claim 1, wherein the salt mixture comprises uranium fluoride.
 3. The eutectic salt according to claim 1, wherein the salt mixture comprises uranium chloride.
 4. The eutectic salt according to claim 1, wherein the salt mixture comprises sodium fluoride and potassium fluoride.
 5. The eutectic salt according to claim 1, wherein the salt mixture comprises sodium fluoride with a molarity of 40-60 mol % and potassium fluoride with a molarity of 40-60 mol %.
 6. The eutectic salt according to claim 1, wherein the salt mixture comprises sodium fluoride, potassium fluoride, and magnesium fluoride.
 7. The eutectic salt according to claim 1, wherein the salt mixture comprises sodium fluoride with a molarity of 40-60 mol %, potassium fluoride with a molarity of 40-70 mol %, and magnesium fluoride with a molarity of 0-20 mol %.
 8. The eutectic salt according to claim 1, wherein the salt mixture comprises sodium fluoride, potassium fluoride, and calcium fluoride.
 9. The eutectic salt according to claim 1, wherein the salt mixture comprises sodium fluoride with a molarity of 40-60 mol %, potassium fluoride with a molarity of 40-70 mol %, and calcium fluoride with a molarity of 0-20 mol %.
 10. The eutectic salt according to claim 1, wherein the salt mixture comprises sodium fluoride with a molarity of 40-60 mol %, potassium fluoride with a molarity of 40-70 mol %, magnesium fluoride with a molarity of 0-20 mol %, and calcium fluoride with a molarity of 0-20 mol %.
 11. The eutectic salt according to claim 1, wherein the salt mixture comprises lithium fluoride, sodium fluoride and potassium fluoride.
 12. The eutectic salt according to claim 1, wherein the uranium fluoride comprises unenriched uranium.
 13. The eutectic salt according to claim 1, wherein the uranium comprises uranium-233.
 14. The eutectic salt according to claim 1, wherein the melting point of the eutectic salt is less than about 600° C.
 15. The eutectic salt according to claim 1, wherein the melting point of the eutectic salt is less than about 710° C.
 16. A molten salt system comprising: a reactor; a salt mixture disposed within the reactor, the salt mixture comprising: uranium, and one or more eutectic salt selected from the group consisting of sodium fluoride, potassium fluoride, aluminum fluoride, zirconium fluoride, lithium fluoride, beryllium fluoride, rubidium fluoride, magnesium fluoride, calcium fluoride, sodium chloride, potassium chloride, aluminum chloride, zirconium chloride, lithium chloride, beryllium chloride, rubidium chloride, magnesium chloride, and calcium chloride; wherein the eutectic salt has a melting point less than about 800° C.
 17. The molten salt system according to claim 16, wherein the uranium fluoride comprises unenriched uranium.
 18. The molten salt system according to claim 16, wherein the uranium comprises uranium-233.
 19. A eutectic salt comprising: a salt mixture comprising: uranium, and one or more salts selected from the group consisting of sodium fluoride, potassium fluoride, lithium fluoride, sodium chloride, potassium chloride, and magnesium chloride; wherein the eutectic salt has a melting point less than about 710° C.
 20. The eutectic salt according to claim 19, wherein the uranium fluoride comprises unenriched uranium.
 21. The eutectic salt according to claim 19, wherein the uranium comprises uranium-233. 